Conventionally, there has been known a fuel supplying device that supplies fuel from a fuel tank of a vehicle to an outside of the fuel tank. In such a fuel supplying device, a fuel pump disposed in the fuel tank takes in fuel from an inlet and discharges the fuel toward the outside of the fuel tank. A device disclosed in Patent Literature 1 (JP 2011-163198 A) includes a suction filter, and a fuel pump takes in fuel from an inlet after filtering the fuel by the suction filter in the fuel tank.
The suction filter disclosed in Patent Literature 1 includes a filter element disposed in the fuel tank. This filter element forms a liquid film when a stored fuel stored in the fuel tank passes through the filter element, and filters the stored fuel. The liquid film is maintained while an outer surface of the filter element is being in contact with the stored fuel. Therefore, in the suction filter of Patent Literature 1, the outer surface of the filter element is partially covered with a side wall member. Accordingly, even when a liquid level of the stored fuel is angled due to bias of the stored fuel during turning of the vehicle and even when the liquid level separates from the filter element, contact of a portion of the outer surface of the filter element with fuel captured between the side wall member and the filter element can be maintained. As a result, in the filter element where the liquid film is maintained, fuel is mainly taken into the inside space having the inlet, and suction of air into the inlet can be suppressed.
In the suction filter disclosed in Patent Literature 1, an inflow opening is defined in the side wall member to allow fuel to flow through between the filter element and the side wall member. Thus, when a vehicle is turning, for example, a liquid level of fuel between the filter element and the side wall member is angled, and therefore the fuel may be likely discharged from the inflow opening according to angles of the liquid level. Thus, when an amount of fuel captured between the filter element and the side wall member decrease, the amount of the captured fuel is exhausted in a short time according to the progress of suction of fuel, and as a result it may be difficult to maintain the liquid film. As a result, air is introduced into an inside space from an outside space of the filter element, and a large amount of fuel remains in the inside space without being taken into the inlet. This is because when a ratio of the volume of air to the volume of the inside space has a specified value or more, only air is substantially taken into the inlet and filtered fuel remains in the inside space. Such suction of air significantly effects on a discharging performance of the fuel pump, and therefore a measure to address this has been required.
In view of the above, it is an objective of the present disclosure to provide a suction filter that stabilizes a discharging performance of a fuel pump, and a fuel supplying device having the suction filter.